A pole mountable solar tracking device

Abstract

A pole mounted dual axis solar tracking apparatus has a main mounting member [ 13 ] in a fixed primary north-south axis which is inclined to accommodate geographical latitude and a cross arm [ 16 ] fixed to the main mounting member and defining a secondary east-west axis. A support frame [ 15 ] for PV panels, solar reflectors etc. is pivoted to the cross arm to enable the support frame to tilt over the secondary east-west axis. The apparatus is highly efficient due to its ability to sweep through the shape of two conjoined cones. The apparatus operates with close to the efficiency of a dual axis tracker but with the simplicity of a single axis tracker.

1 . A dual axis solar tracking apparatus mountable at the top of a central support tower, the apparatus comprising:
 a main mounting member adapted for rotation relative to the central support tower about a fixed inclined primary axis defining a north south axis;   a support frame adapted to support a component for receiving solar energy;   attachment means to attach the support frame to the main mounting member;   pivot means to enable the support frame to pivot relative to the attachment means about a secondary axis defining an east west axis; and   adjustment means to enable the tilt angle of the support to the attachment means to be adjusted;
 whereby, in use, pivoting of the main mounting member about the fixed inclined primary axis causes the support frame to track the sun from east to west and whereby, the support frame is pivoted about the secondary axis for adjusting an inclination of the support frame to accommodate seasonal variations of positions of the sun. 
   
     
     
         2 . The apparatus of  claim 1  including a mount at the top of the central support tower, the mount defining the inclined primary axis, the main mounting member being rotatable about the mount thereby causing the main mounting member to rotate about the inclined primary axis. 
     
     
         3 . The apparatus of  claim 2 , wherein the component for receiving solar energy comprises PV panels, solar reflectors, solar heaters or a combination thereof. 
     
     
         4 . The apparatus of  claim 1 , wherein the central support tower comprises a pole, mast or tower. 
     
     
         5 . The apparatus of  claim 1 , wherein the attachment means comprises a cross arm fixed to the main mounting member, the cross arm having opposed ends, each end including a said pivot means to enable the support frame to pivot relative to the attachment means about a secondary axis defining an east west axis. 
     
     
         6 . The apparatus of  claim 1 , wherein the adjustment means comprises at least one linear actuator. 
     
     
         7 . The apparatus of  claim 6 , wherein the linear actuator comprises a threaded rod rotatable about its longitudinal axis, the rod being operatively connected to the support frame, whereby rotation of the rod causes tilting of the support frame. 
     
     
         8 . The apparatus of  claim 7 , wherein the linear actuator comprises a threaded rod, a traveling nut threadingly engaged about the threaded rod, at least one connecting member attached to the nut and to the support frame, whereby rotation of the rod causes movement of the nut along the rod and tilting of the support frame about the secondary axis. 
     
     
         9 . The apparatus of  claim 7  or  8 , wherein the nut passes daily over a cam on the central support tower thereby changing the length of the arm and the inclination of the array frame 
     
     
         10 . The apparatus of  claim 1  including a drive to drive the apparatus about the primary north-south axis, the drive comprising a rack attached to the attachment means and rotating through a defined arc upon rotation of the apparatus by the drive means, and a motor supported by the central support tower and coupled to the rack for driving thereof. 
     
     
         11 . The apparatus of  claim 10 , wherein the rack is semicircular and is attached to the attachment means adjacent ends of the attachment means to provide robust support for the apparatus. 
     
     
         12 . The apparatus of  claim 11 , wherein the adjustment means comprises a linear actuator having one end attached to the rack and another end attached to the support frame. 
     
     
         13 . The apparatus of  claim 1 , wherein the mount on top of the support and the main mounting member comprise hinge leafs each including at least one knuckle, and a hinge pin extending through the knuckles to hinge the leaf together, the pin defining the primary axis. 
     
     
         14 . The apparatus of  claim 1 , wherein the mount on top of the support is bifurcated, each bifurcated arm supporting a hinge pin, the pins defining the primary axis, the main mounting member being pivotly attached to the pins. 
     
     
         15 . The apparatus of  claim 1 , wherein the adjustment means about the secondary axis comprises a locking plate attached to the support frame with multiple openings to accept a locking bolt, the bolt fixing the support frame to the attachment means at a particular inclination. 
     
     
         16 . The apparatus of  claim 1 , wherein the pivot means to enable the support frame to pivot relative to the attachment means about a secondary axis defining an east west axis is such that the secondary axis intersects at or close to the central vertical longitudinal axis of the pole. 
     
     
         17 . The apparatus of  claim 16 , wherein the support frame and the attachment means and any attached component for receiving solar energy are designed such that the weight is approximately balanced to each side of the secondary axis.